The mission of the NCI/CCR/LP Clinical Cytogenetics Section is to provide state-of-the-art diagnostic services for patients evaluated and treated at the Mark O. Hatfield Clinical Research Center; to perform clinical translational cancer cytogenetics research; and to teach and mentor students, residents, and fellows in the principles and practices of clinical cytogenetics service and research. The goals of this project, which comprises 80 percent of the effort of the section, are to provide diagnostic service and research testing on samples from patients entered on clinical research protocols by NCI and other Institute physicians, to collaborate on NCI clinical translational research protocols, and to teach and mentor students, residents, and fellows.The Clinical Cytogenetics Section is the only intramural NIH laboratory performing cytogenetics diagnostic services. The laboratory is inspected and certified by the College of American Pathologists, the Joint Commission for Accreditation of Hospitals, and the Clinical Laboratory Improvement Act of 1988. We currently perform highly complex routine and molecular cytogenetic testing on patient samples from several institutes (NCI, NIAID, NICHD) and the Clinical Center Department of Laboratory Medicine. In greater than 80 percent of cases the testing is for acquired chromosome abnormalities in premalignant and malignant disorders, and in the remaining cases is for constitutional chromosome abnormalities. The results of our testing are used for diagnosis, classification, prognosis, and treatment planning for patients. They also provide critical information regarding the gene regions that may be important for tumor initiation and progression, and thus serve as a starting point for further molecular biologic investigations of malignant diseases.Section members are conducting routine diagnostic and research fluorescence in-situ hybridization (FISH), comparative genomic hybridization (CGH), and spectral karyotyping (SKY) analyses of patients entered on NCI clinical research protocols. Dr. Arthur is an Associate Investigator on seven active protocols as follows:a. 97-C-0178 "Fludarabine Treatment of Chronic Lymphocytic Leukemia (CLL): cDNA Microarray Gene Expression Analysis, and Pre-Clinical Bone Marrow Transplant/ Immunotherapy Studies," PI: Wyndham Wilson, M.D., Ph.D. b. 01-C-0125 "Pilot Study of Non-myeloablative, HLA-matched Allogeneic Stem Cell Transplantation for Pediatric Hematopoietic Malignancies," PI: Alan S. Wayne, M.D.c. 02-C-0052 "Etiologic Investigation of Cancer Susceptibility in Inherited Bone Marrow Failure Syndromes," PI: Blanche Alter, M.D. M.P.H. d. 04-C-0079 "Pediatric Phase I Trial of BL22 for Refractory CD22-Positive Leukemias and Lymphomas," PI: Alan S. Wayne, M.D.e. 04-C-0102 "Hematologic Malignancy Biology Study," PI: Alan S. Wayne, M.D.f. 04-C-0168 "Pediatric Phase I Trial of LMB-2 for Refractory CD25-Positive Leukemias and Lymphomas," PI: Alan S. Wayne, M.D.g. 04-C-0095 "A Pilot Study of Intensified Lymphodepletion Followed by Autologous Hematopoietic Stem Cell Transplantation in Patients with Severe Systemic Lupus Erythematosus," PI: Steven Z. Pavletic, M.D.The cytogenetics data generated as part of these studies are clinically useful for diagnosis, classification, and treatment planning for patients. They are also important for monitoring patient response to experimental treatment, and for correlation with other research studies. They have the potential for discovery of new clinical-pathological associations among these diseases and of biological mechanisms that may be targeted with future therapies. Finally, section members teach and mentor students, residents, and fellows in the principles and practices of clinical cytogenetics service and research.